>> Apple's business model regarding macOS is to sell as many devices as possible capable of running that operating system.

> I don't agree that this particular trait of macOS makes an implementation at the layer WINE implements (full API+ABI) any harder or easier.

Here is my corroboration. Apple publishes XNU to the world in this repository:

  https://github.com/apple-oss-distributions/xnu

> I do think there is an argument to be made that Win32 was more straightforward ...

I did not make that argument. Instead, the position I hold regarding Windows is:

  ... an independently derived emulation layer is
  possible (not easy, just possible) ...

In fact, you have made my point for me:

> ... while slow change is useful, backwards compatibility expands the Win32 API surface area, since each API also needs to continue to support every way it was ever wrongly used.